Source:

Response:

Convergent evolution has long been known to occur in large structures,
such as the wings of bats and birds. It has long been expected in the
structure of molecules, too. Roux et al. (1998) say, "Evolutionary
convergence at the molecular level is presumed to be widespread, but is
poorly documented." The protein they describe is one example.

Similarities can be explained under evolution as due to inheritance,
convergence, or chance. In the case of convergence, we expect similar
selective pressures on the organisms with the similarities, and we
expect dissimilarity in smaller details of the structure. This is what
we observe here. The DNA sequences that code for the proteins are
different between sharks and camels (Roux et al. 1998).